???
A previous answer pointed out ?toeplitz
entering
> toeplitz
gives
{
if (!is.vector(x))
stop("'x' is not a vector")
n <- length(x)
A <- matrix(0, n, n)
matrix(x[abs(col(A) - row(A)) + 1], n, n)
}
Why reinvent?
-- Bert
On Fri, Sep 7, 2012 at 8:19 AM, David L Carlson <dcarl...@tamu.edu> wrote:
> You asked for existing functions, but I was more intrigued by trying to
> create one:
>
> symmat <- function(n) {
> x <- matrix(1:n, nrow=n, ncol=n)
> abs(x-col(x))+1
> }
>
>> symmat(4)
> [,1] [,2] [,3] [,4]
> [1,] 1 2 3 4
> [2,] 2 1 2 3
> [3,] 3 2 1 2
> [4,] 4 3 2 1
>
> ----------------------------------------------
> David L Carlson
> Associate Professor of Anthropology
> Texas A&M University
> College Station, TX 77843-4352
>
>
>> -----Original Message-----
>> From: r-help-boun...@r-project.org [mailto:r-help-bounces@r-
>> project.org] On Behalf Of Erin Hodgess
>> Sent: Thursday, September 06, 2012 8:11 PM
>> To: R help
>> Subject: [R] creating a symmetric matrix
>>
>> Dear R People:
>>
>> Suppose I have the following:
>>
>> x <- 1:4
>>
>> And I want to create the following matrix:
>>
>> 1 2 3 4
>> 2 1 2 3
>> 3 2 1 2
>> 4 3 2 1
>>
>> Is there a function in place for this, please? I looked at symMatrix
>> in micEcon and some of the items in Matrix, but they didn't quite do
>> it.
>>
>> I can put together something quickly, of course, but it seems likely
>> that this would exist.
>>
>> Thanks,
>> Erin
>>
>>
>> --
>> Erin Hodgess
>> Associate Professor
>> Department of Computer and Mathematical Sciences
>> University of Houston - Downtown
>> mailto: erinm.hodg...@gmail.com
>>
>> ______________________________________________
>> R-help@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-
>> guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
--
Bert Gunter
Genentech Nonclinical Biostatistics
Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
______________________________________________
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and provide commented, minimal, self-contained, reproducible code.
